/* codebar.avr.c */ /* robospierre - Eurobot 2011 AI. {{{ * * Copyright (C) 2011 Nicolas Schodet * * APBTeam: * Web: http://apbteam.org/ * Email: team AT apbteam DOT org * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * }}} */ #include "common.h" #include "codebar.h" #include "defs.h" #include "modules/twi/twi.h" #include "modules/utils/utils.h" #include "modules/utils/crc.h" #include "modules/utils/byte.h" #define CODEBAR_ADDRESS 0x20 #define CODEBAR_STATUS_LENGTH 7 void codebar_init (void) { } uint8_t codebar_get (uint8_t direction) { uint8_t buffer[CODEBAR_STATUS_LENGTH]; /* Read status. */ twi_master_recv (CODEBAR_ADDRESS, buffer, sizeof (buffer)); uint8_t ret = twi_master_wait (); if (ret != CODEBAR_STATUS_LENGTH) return 0; uint8_t crc = crc_compute (buffer + 1, CODEBAR_STATUS_LENGTH - 1); if (crc != buffer[0]) return 0; /* Get data. */ uint8_t offset = direction == DIRECTION_FORWARD ? 1 : 4; uint16_t age = v8_to_v16 (buffer[offset], buffer[offset + 1]); uint16_t type = buffer[offset + 2]; if (age > 3 * 250) return 0; else return type; }